forces and motion ༊*·˚

Question 1

what quantities only have magnitude ?

Answer 1

scalars.

Question 1

what quantities have both direction and magnitude ?

Answer 1

vectors.

Question 2

what can vector quantities be shown with ?

Answer 2

arrows.

Question 3

what is a force ?

Answer 3

a push or a pull that acts on an object due to interaction with another object.

Question 4

what are the two main types of forces ?

Answer 4

contact or non-contact

Question 5

list examples of contact forces ?

Answer 5

examples of contact forces are friction, air resistance, tension and normal contact force.

Question 6

list examples of non-contacts forces ?

Answer 6

examples of non-contact forces are gravitational force, electrostatic force and magnetic force.

Question 7

what type of quantity is force ?

Answer 7

force is a vector quantity.

Question 8

what is weight ?

Answer 8

weight is a force acting on an object due to gravity.

Question 9

why is the force of gravity close to earth ?

Answer 9

the force of gravity close to the earth is due the gravitational field around the earth.

Question 10

what does the weight of an object depend on ?

Answer 10

the weight of an object depends on gravitational field strength at the point where the object is.

Question 11

how is the weight of an object calculated ?

Answer 11

the weight of an object can be calculated using w=mg (weight in newtons, mass in KG, and gravitational field strength in N/KG

Question 12

what does it mean to say that the the weight of an object acts at its centre of mass ?

Answer 12

the weight of an object may be considered to act at a single point, referred to as the centre of the object’s mass.

Question 13

how is weight measured, and what instrument is commonly used for this purpose ?

Answer 13

weight is measured using a calibrated spring-balance called a newton meter.

Question 14

describe the relationship between the weight and mass of an object.

Answer 14

the weight of an object and the mass of and object are directly proportional.

Question 15

what is meant by the term “resultant force” and how is it related to multiple forces acting on an object ?

Answer 15

a number of forces acting on an object may be replaced by a single force that has the same effect as all of the original forces together. the single force is called the resultant force.

Question 16

state newton’s third law of motion and explain its significance in understanding force interactions ?

Answer 16

every action has an opposite and equal reaction.

Question 17

explain the concept of newton pairs and provide examples illustrating this principle.

Answer 17

the newton pair force for your force pushing down on the floor is the contact force of the floor up on you. the newton pair force for your weight is the force you pull up with on the centre of the earth of the earth due to gravity.